Step 1: Locate the Maldives strategically.
The Maldives lies astride critical Sea Lines of Communication (SLOCs) in the Indian Ocean through which a major share of India’s trade and energy shipments pass.
Step 2: Link to India's security calculus.
Control, surveillance, and friendly access around these SLOCs are essential for India’s maritime domain awareness, anti-piracy/terror operations, disaster response, and protection of shipping.
Step 3: Eliminate alternatives.
Energy resources (A) are not the primary attraction; political alliance with {Europe} (C) is unrelated; cultural ties (D) exist but are not the {primary} strategic reason.
Step 4: Conclude.
\[
\boxed{\text{India’s prime interest is maritime security in the Indian Ocean (Option B).}}
\]